1221200019999 has 72 divisors (see below), whose sum is σ = 1834297566192. Its totient is φ = 782527495680.

The previous prime is 1221200019953. The next prime is 1221200020009. The reversal of 1221200019999 is 9999100021221.

It is not a de Polignac number, because 1221200019999 - 2¹⁷ = 1221199888927 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221200014999) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2507597334 + ... + 2507597820.

It is an arithmetic number, because the mean of its divisors is an integer number (25476355086).

Almost surely, 2^{1221200019999} is an apocalyptic number.

1221200019999 is a deficient number, since it is larger than the sum of its proper divisors (613097546193).

1221200019999 is an equidigital number, since it uses as much as digits as its factorization.

1221200019999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237 (or 747 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 45.

The spelling of 1221200019999 in words is "one trillion, two hundred twenty-one billion, two hundred million, nineteen thousand, nine hundred ninety-nine".